Joe Schmidt’s men prevailed in Rome through Conor Murray and Tommy O’Donnell sneaking tries while Italy hooker Leonardo Ghiraldini was in the sin-bin.

The lacklustre visitors seized their extra-man advantage to seal a victory lacking any style, but lost luckless flanker Sean O’Brien to a hamstring injury suffered in the warm-up.

Ian Keatley made his overdue RBS 6 Nations debut as the 27-year-old fly-half deputised for Lions playmaker Johnny Sexton, who will return to face France in Dublin next weekend after a 12-week concussion lay-off.

Italy had back-row agitators Sergio Parisse and Alessandro Zanni back in tandem, with New Zealand-born fly-half Kelly Haimona leading the line.

Flanker Sean O'Brien pulled out of Ireland's line-up in the warm-up just minutes before kick-off, nursing his hamstring.

The luckless Leinster man’s injury problems rumble on. The 27-year-old has still not featured in Test action since November 2013.

O’Brien had ice strapped to his left hamstring as he took to the bench to watch the match.

Italy proved the architects of their own discomfort right from the off, Matias Aguero penalised for slipping his bind at the scrum.

George Biagi’s cheap knock-on gifted Ireland field position, and a pointless midfield offside allowed Keatley to open the scoring from the tee.

Jack McGrath atoned for conceding a scrum penalty by winning a fine choke-tackle turnover, in tandem with Peter O’Mahony.

Munster fly-half Keatley endured a mixed opening quarter, slotting his penalty calmly, but throwing a loose pass and also being charged down by Michele Campagnaro.

Ireland threatened through careful build-up, only for Simon Zebo to knock on Conor Murray’s ambitious inside pass.

All the fizzing electricity from England’s tournament opening 21-16 win over Wales in Cardiff turned to dismal static in a humdrum first half in Rome.

Keatley doubled his and Ireland’s tally after Luke McLean wandered offside to retrieve Andrea Masi’s knock-on.

For all their possession however, Ireland lacked any spark. Joe Schmidt’s men fought hard for fluency, but settled instead for stoic territorial control.

Keatley had to scamper to retrieve a loose miss-pass from Murray, while Robbie Henshaw knocked on out wide.

Ireland drove close from a lineout maul, but Tommy Bowe could not tap Murray’s deft chip back inside with enough space for the scrum-half to wriggle home.

The visitors had to settle instead for Keatley’s third penalty of the afternoon.

Italy then set up camp in Ireland’s 22 but after one driving maul Kelly Haimona opted to strike at goal.

The New Zealand-born fly-half landed the goal to cut Italy’s deficit to six points at the break.

Ireland started the second half searching for some kind of fuel injection, but still their attack misfired.

Keatley produced a neat half-break on the blindside, only to force an attempted final pass. Campagnaro knocked on trying to intercept, allowing Ireland a quick wipe of the brow.

Keatley almost cut the line again in Italy’s 22, but Parisse produced a fine ruck steal to ease the pressure.

Jared Payne raced close after Simon Zebo’s neat wide pass, but Robbie Henshaw knocked on trying to sneak through.

Payne and Henshaw noticeably picked up the pace after the break, but again Ireland turned to Keatley’s boot to extend their lead to 12-3.

Ireland dispensed with posting penalties, instead going for the jugular just past the hour, punting to the corner for an attacking line-out.

Leonardo Ghiraldini spoiled Ireland’s maul from an offside position and was duly sin-binned for his troubles.

Ireland went straight for the lineout once more and finally broke the try deadlock.

Murray wriggled home after the pack drove to the whitewash, with Keatley converting for a 19-3 lead.

No sooner had Ireland scored than boss Joe Schmidt brought off Keatley, Paul O’Connell and Peter O’Mahoney, no doubt with one eye on next weekend’s France clash.

Tommy O’Donnell then raced through Italy’s porous midfield to rubber-stamp Ireland’s victory.

Ian Madigan slotted the conversion to add gloss to the scoreline, but Ireland were unable to maintain that momentum once Italy were restored to full complement.

Italy’s rally forced Ireland to defend with zeal and composure at the death when Schmidt’s men would sooner have been attempting to boost their points-difference tally.

Andrea Manici’s sloppy spilled ball dented Italy’s momentum before Haimona had a try ruled out for the slightest of knock-ons from Parisse.